Electric high-frequency signaling apparatus



V. K. ZWORYKIN Filed Aug. 28.

ELECTRIC HIGH FREQUENCY SIGNALING APPARATUS Feb. 19 1924.

atent Feb. 19, 1924.

VLADIMIR K. ZWORYKIN, OF KANSAS CITY, MISSOURI.

v ELECTRIC HIGH-FREQUENCY SIGNALING APPARATUS.

Application filed August 28, 1922. Serial No. 584,716.

' To all whom it may concern Be it known that I, VLADIMIR K. ZWORY- KIN,a citizen of the Republic of Russia, and

resident of Kansas City, county of Jackson, State of Missouri, haveinvented a certain new and useful Improvement in Electric High-FrequencySignaling Apparatus, of which the following is a complete specification.

vided on each train, whereby the oscillating circuits will be mutuallyaflected through the track rails, upon approach of the two trains withina predetermined distance of each other, with the result that signalswill be producedin both circuits onaccount of beat waves or notes set uptherein in response to slight variations in the continuous wavefrequencies. 7 y

For carrying out. the wayside signaling operation, stationary loopantennae are provided which are of such a character as to absorb theenergy of the oscillator or train circuit, thus automatically effectingthe production of a signal or operation of suitable relays; or, suchstationary loop antennas may be in circuit with suitable oscillatorapparatus of a signal station whereby the high frequency current of theoscillator circuit of the train -may be modulated and thereby caused toinfluencethe signaling instruments or controlling relays of thetraincircuit.

With these general objects in view, the invention will now, be describedby reference to the accompanying drawing illustrating one method which Ihave devised for carry-- ing out the invention in practice, after whichthose features which I deem to be novel will be particularly set forthandclaimed.

In the drawing- Figure 1 is a diagram illustrating the cir-.

'tively low-power tube oscillators may cuit arrangement of a signalingsystem em bodying the present invention;

Figure 2 is a plan View showing a wayside absorbing loop antennadesigned to influence the train circuit; and

Figure 3 is asimilar view showing a wayside loop antenna, designed to beincluded in the circuit of a signaling station.

Referring now to the drawing in detail, this shows in Figure 1 acontinuous wave high frequency oscillatory circuit designated in generalby the referenceletter -A and designed to be installed on the locomotiveof a train or other vehicle. The antenna loop 10 of this circuit issuspended beneath the 10- comotive adjacentto the track 11, and theconductor 12 of the antenna may be placed in circuit with the rails ofthe-track 11, through the wheels 13 of the locomotive,

and, ifthe locomotive is attached to a train,

by means of suitable parallel connections 12' with the conductor 12,with the wheels of all the cars of the train. Any wellknown oscillatorycircuit can be used for this purpose, particularly a circuit generatmgoscillations having a constant wave length. Referring to the drawing,this circuit is shown as consisting of an oscillatory tube. 16 (of whichas many may be used as desired) operating at the same time as adetector, and an amplifier tube 18, of which likewise any number may beemployed, according to conditions. This circuit arrangement is such asto act both as a means for generating continuous waves of high frequencyand also as a'receiver, with one or many stages of plifications.

The load circuit is represented'by the loop relatively low frequency am-10 coupled with the inductance of the oscillatory circuit A. The currentin this last circuit is measured by the thermal ammeter or thermal relay5. The amplifier 18 is connected to the loud speaker or special relay19. It is well known that steelrails are poor conductors for shortwaves, but that oscillations emitted even by compara; readilytransmitted through such rails for a distance of a few thousand yards.Ac-. cordingly, if a second locomotive. be equipped with an oscillatorycircuit A, similar to the circuit A above described, and then either orboth of the two locomotives carrying the circuits A and A begin toapproach one another, the circuits will exert no appreciable influenceupon each other until after the distancebetween them has been decreasedbelow a definite predeter mined limit. What is known as the heterodyneeffect will then take place by virtue of any slight difference occuringin the wave frequencies in the two circuits; this results in theproduction of beat waves or notes of lower frequency in both circuits,which beat notes are amplified by the low frequency amplifier andthereby rendered audible when transmitted to the loud speak or 19. Noreal necessity arises for tuning the two oscillatory circuits fordifierent wave lengths because in practice it is found that the shortwave oscillator is subject to more or less automatic change in wavelength, particularly durin the movement of the train; if deemedadvlsable, however, a condenser 21 may be constructed in such a way thatthe movement of the trains will produce any desired variation infrequency.

If either locomotive is attached to a train, the conductor 12 isconnected in parallel (by means of the connections 12) with the wheelsof all the cars of the train, as above explained. By this arrangement itis apparent that the apparatus of one locomotive will at once detect thepresence of a whole train which may be approaching within thepredetermined distance. above referred to; in other words, the length ofthe train will be immaterial. and the warning signal will be givenwhenever the distance between the locomotive of one train and the lastcar of the other train-is less than said predeter-. mined limit.

The apparatus of neither locomotive will be actuated to produce anysignals by the the load of such circuits.

presence of trains on diiferent or parallel tracks, because of therebeing no electrical connection between the tracks other than through theground.

Referring now to Figure 2, I propose locating at suitable intervalsalong the track,

. or at any points where it may be desired to eflect a signal operation,an absorbent loop antenna 24 which may be tuned for the same wavefrequency as the circuits A and A of the trains, and with resistancerepresenting With this arrangement it will be understood that when I theantenna loop 10, of the train is carried over one of the ops 24, thelatter will absorb the energy ofthe train circuit, just as a wave meterabsorbs the energy from an ordinary transmitter. This produces a drop inthe current of the train circuit, adapted to be registered by an ammeteror specialrelay 5 in the locomotive cab. This constitutes an effectivemeans of transmitting signalsfrom any desired wayside points, at veryslight cost for the wayside apparatus, the absorbing loops 24 beinginexpensive and of a portable character, adapted to be locatedtemporarily at any point as required in track reconstruction or otheremergency Work; 7

Referring now to Figure 3, this illustrates a wayside antenna loop 30,similar to the loop 24 but connected with a conductor 32 representingpart of a signal station circuit whereby a suitable oscillatory current,for lnstance the current from a microphone or other source, may beintroduced in the loop ing either audible or visible signal indlca- Itions, or for operation through relays to apply the brakes or controlthe motive power applied to the train, all of which is of meremechanical practice in the adaptation of the improvements herein toperform the desired functions.

From the foregoing it will be apparent that I have devised'a signalsystem characterized by these features of improvement,

viz, the generating of: continuous or undamped waves by a trainoscillatory "circuit for transmitting purposes, and the employment ofthe same circuit for receiving 'pur-.

poses, whereby the same beat notes (or signals) will be produced in bothcircuits of two rains approaching each other within a given distance;and the use of the same type of oscillatory circuit for receivingsignals in response to the action of an absorbent wayside antenna loopoperating to produce a drop in the current of the train ci-rcuit, or inresponse to the action of a signal station loop antenna operatingtomodulatc the train circuit. A signal system having this arrangementand construction and made of operation is attendedby various distinctadvantages, such as the fact that no overhead aerial'of the usual typeis required for transmitting the signals, the track being used for thepropagation of'the waves, on the socalled guided wave telegraphyprinciple that no special characteristic wave length is required foreach train, the trains being tuned for the same wave length and the beator signal notes of audible frequency being produced by the heterodyneaction of the oscillatory circuits upon approaching within apredetermined distance of each other as above explained; and the furtherfact that, by means of extremely simple and inexpensive way'side'antennaloo devices, the same train circuits may be in uenced to effect thereceiving of various signals from outside sources.v

' proximately \Vhile I have illustratedgand described what I now deem toconstitute the preferred mode of practicing the invention, I desire toreserve the right to make all such changes or modifications as mayfairly fall within the, scope of the appended claims.

What I claim is that- 1. Electric signaling apparatus comprising twooscillatory circuits emitting continuous waves of high frequency and ofapthesame wave length, said circuits being operative on relativeapproaching movement within a given predetermined distance to set upslight variations in wave length producing beat waves of lowerfrequency, and signal emitting means included in each of said circuitsfor actuation in response to said heat waves.

2. Electric train signaling means comprising, in combination with thetrack rails, an oscillatory circuit adapted to be carried by a train andhaving an antenna suspended adjacent said rails and emitting continuouswaves of high frequency, said circuit being adapted to be influenced bya similar circuit .carried by a relatively approaching train within agiven predetermined distance to generate beat waves of lower frequency,and signal emitting means included in said circuit for actuation inresponse to said beat waves.

'3. Electric train signaling means comprising, in combination with thetrack rails,

' a heterodyne oscillatory circuit electrically connected to said trackrails adapted to be carried by a tram and having an antenna loopemitting continuous high frequency waves and adapted to be maintained incontinuous inductive relation to saidrails.

4. Electric train signaling means comprising. in combination with thetrack rails, an oscillatory circuit electrically connected to said trackrails adapted to be carried by a train and having an antenna suspendedadjacent said rails. an absorbent loop antenna located along said trackand operative inductively to absorb the energy of said oscillatorycircuit, and currentoperated means included in said circuit foractuation in response to the inductive action of said absorbent loop.

5. Electric train signaling means comprising, in combination with thetrack rails, an oscillatory circuit adapted to be carried by a train andhaving an antenna suspended adjacent said rails, an exciting loopantenna located along said track and operative inductively to modulatethe current of said oscillatory circuit, and current-operated meansincluded in-said circuit for actuation inresponse to the inductiveaction of said antenna.

(5. Electric railway signaling apparatus comprising a moving oscillatorycircuitemitting continuous waves of high frequency and adapted toreceive from a similar circuit continuous wave signals by the heterodynemethod, said circuit having an. antenna loop adapted for travel adjacentthe. track rails, in combination with an absorbent loop antenna locatedalong said track rails and operative inductively to absorb the energy ofsaid moving oscillatory circuit.

7. Electric railway signaling apparatus comprising a moving oscillatorycircuit emitting continuous waves of high frequency and adapted toreceive from a similar circuit continuous wave signals by the heterodynemethod, said circuit having an antenna loop adapted for travel adjacentthe track rails, in combination with an exciting loop antenna located along said rails and operative inductively to modulate the current ofsaid moving oscillatory circuit.

8. Electric railway signaling apparatus comprising a moving oscillatorycircuitemitting continuous waves of high frequency and adapted toreceive from a similar circuit continuous wave signals by the heterodynemethod. said circuit having an antenna loop adapted for travel adjacentthe track rails, in combination with absorbent and exciting loopantenna: located at intervals along said rails and operative,respectively, to inductively absorb the energy of said movingoscillatory circuit or to modulate the current, of said circuit.

. In witness whereof I hereunto afiix my signature.

VLADIMIR K. ZVVORYKIN.

